Okay update again, in case any of you wonderful posters who have helped are interested:
Tried her in arena yesterday after a very good no incident session in the roundpen. Now mind you the arena is a mess as we are replacing the fencing. (there are piles of wood, fence material, etc) I hand walked her quite a bit and then got on. She acted up almost immediately, running to the far end where there are trees she knew would knock me in the head. Tried rearing and then stopping all together.
I finally got her to walk around and then finished on a sorta good note.
Today I just walked her all over the arena then lunged her. Every time she was good I stopped for a while and let her eat grass. She actually got bored of the grass and wanted to go back to work!
I then let her graze when we were done and have some treats and she was very calm. Tmrw will try to get on her again and see where we are.